Hairdryer including a safety device

ABSTRACT

A hairdryer including a safety device is characterized in that the safety device is designed for detecting a jamming, even partial, of the hairdryer air suction fan.

BACKGROUND OF THE INVENTION

The present invention relates to a hairdryer including a safety device.

As is known, the air inlet filter of a hairdryer must be always held ina perfectly cleaned condition to provide a maximum efficiency of theapparatus and to prevent failures and overheating from occurring.

In fact, air residues, mixed with powder and fixing or adhesivesubstances, and being sucked during the operation, are easily depositedup to fully close the air passage, thereby overheating the hairdryeroperating motor.

Moreover, the hairdryer heating resistance cannot be properly cooled,thereby the thermostatic switch of the hairdryer is compelled tocontinuously operate while providing alternately excessively cold or hotair.

In such a condition, the apparatus does not properly operate and it issusceptible to failures and safety problems.

Up to now, the hairdryer filter and cleaning thereof were performed bythe user by merely seeing the filter condition.

Such a visual detection, however, depends of the user, and does not meetthe minimum efficiency requirements imposed by the hairdryer maker for asafe operation of the hairdryer.

The above mentioned problems are further compounded in a professionaluse by hair processing operators.

In fact, in hair shops, where skilled but also non skilled operators arepresent, the filter is rarely examined and cleaned, with a consequentfailure of the related hairdryer.

SUMMARY OF THE INVENTION

Accordingly, the aim of the present invention is to provide a hairdryerincluding a safety device designed for overcoming the above discloseddrawbacks.

Within the scope of the above aim, a main object of the invention is toprovide such a hairdryer including a detecting device designed forsafely detecting a possible jamming of the hairdryer filter.

Another object of the present invention is to provide such a hairdryerincluding a safety device designed for switching off the operation ofthe hairdryer or designed for providing a failure signal, as the filteris jammed or clogged beyond a safety threshold set by the hairdryermaker, to allow the operator to timely clean the filter.

Yet another object of the invention is to provide such a safety devicefor hairdryers which has a very small size, to be easily housed in thehairdryer and which allows the hairdryer to always properly operate, andthis by using constructional materials and technique as commerciallyavailable.

According to one aspect of the present invention, the above mentionedaim and objects, as well as yet other objects, which will become moreapparent hereinafter, are achieved by a hairdryer including a safetydevice, characterized in that said safety device is adapted to detect aclogging or jamming, even partial, of the air inlet filter applied atthe air inlet opening of the hairdryer.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the present invention willbecome more apparent hereinafter from the following detailed disclosureof a preferred, though not exclusive, embodiment of the invention, whichis illustrated, by way of an indicative, but not limitative example, inthe accompanying drawings, where:

FIG. 1 is a schematic side elevation view, as longitudinallycross-sectioned, of a hairdryer including a safety device according tothe present invention;

FIG. 2 is a rear elevation view of the hairdryer shown in FIG. 1;

FIG. 3 is a further perspective view of that same hairdryer; and

FIGS. 4 and 4A show a diagram of the electronic control circuit.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the number references of the above mentioned figures,the hairdryer according to the invention, which has been generallyindicated by the reference number 1, comprises a box-like body,including a rear shell 2 and a front shell 7 and designed for holdingtherein an operating motor and heating means comprising a heatingresistance or the like, in a per se known manner.

The rear shell 2 comprises an opening or port, to which a screen or meshfilter 5 adapted to be locked by a filter ring nut 3, is applied.

In a per se known manner, said filter 5 is adapted to operate as a dirtbarrier for preventing dirt present in environment air from entering thehairdryer.

According to the present invention, the hairdryer further comprises asafety device for detecting a jamming or clogging, even partial, of thefilter 5.

As shown, the safety device comprises a photosensor 4, for sensing thelight intensity through the filter 5.

As said light intensity decreases because of the clogging of the filtermesh, by said dirt material, the sensor 4 will send a signal which,through a suitably designed electronic circuit 6 will operate a lightindicating element 11, or other signaling means, which will be switchedon with an intermittent or continuous light.

Said electronic circuit 6 can also be used for other applications, suchas, for example, a moisture sensor.

The light indicating element 11 may be arranged between the rear shell 2and the filter ring nut 3, as shown in FIG. 1, or between the two frontand rear shells, as shown in FIG. 3, or in any other suitable positions.

The light photosensor 4 can be arranged at the center of the filter ringnut 3, and being spaced, therein inside, from the mesh or screen filter5.

The electronic circuit 6 can be arranged in the hairdryer handle 12 orany other region inside the hairdryer body.

Said safety device can comprise an automatic switch for switching offthe fan motor and heating resistance, as said sensor detects that thefilter is clogged beyond a preset threshold level.

Advantageously, the safety device further comprises an environment lightdetector, to allow said safety device to also operate as the environmentlight changes.

The environment light detector, comprising a resistor and generallyindicated by the reference number 13, can be arranged on the hairdryerbody, for example at the air inlet thereof.

Said electronic circuit substantially comprises an electronic card,shown in FIG. 4, including a single surface printed board thereon areassembled the operating components and, on the outside thereof beingmoreover provided a phototransistor, a photoresistor, and a power supplyassembly.

The safety device operates as follows.

The electronic card is arranged inside the body of the hairdryer.

To said card are electrically coupled said electric power supply,phototransistor 4 and photoresistor 13.

The phototransistor, as suitably arranged, will read the light amountpassing through the mechanical filter of the hairdryer.

The photoresistor, arranged at a different position from that of thephototransistor, will read the environment light amount.

The light amount read out by the phototransistor will define thecondition of clean filter or dirty or clogged filter and, moreprecisely, based on a value x.

If this values x is exceeded, then the filter is considered as dirty orclogged.

The light amount read out by the photoresistor will set the environmentlight amount and, depending on this value, a feed back to the value readout by the phototransistor will be performed, by proportionatelytranslating the dirty filter values.

The card further includes herein a LED diode of a red color.

This diode will be held in a switched off condition if the filter is ina cleaned condition.

It will be switched on only as the card is power supplied and the filteris considered as dirty.

As the power supply to the card is switched off, said LED will be alsoswitched off and, as it is switched on again, the light amounts on thephotodetectors will be read again, while switching on the red LEDdepending on this read-out.

The card will be power supplied simultaneously with the fan motor, whilecontrolling the light amount on the phototransistor and on thephotoresistor, the operation of the card being that which has been abovedisclosed up to its switching off.

The photodetectors are read out after about a second from the power upof the card, since the signals must be stabilized, and the othersubsequent read-outs will be repeatedly performed at even intervals upto the switching off of said card.

A dirty filter signal will be considered as valid only after someconsecutive seconds with the same result; the same thing occurs for theclean filter signal.

This allows to remove false read-outs due to noise and the like.

As the dirty filter condition is detected, the red LED will be switchedon and switched off again, if a new cleaned filter condition isdetected, with the above disclosed procedure or exclusively as the cardis switched off.

The electronic circuit is preferably made as hereinafter disclosed, withreference to FIG. 4.

All the components connected downstream of the power supply operateunder a low voltage.

From a starting AC middle voltage, a low voltage of about 5 Vcc has beenobtained.

The reference number 21 shows a resistor Ri designed for providing apotential difference at the ends thereof, to provide a low voltage dueto a resistive loss.

The high value of this component and its rated power also operate toeliminate the surge type noises which could arrive from the power supplynet and provide failures to the electronic card.

The reference number 22 indicates the components PD1, DZ1 and C1,downstream of the resistor Ri.

PD1 is a diode bridge operated to modify the voltage waveshape from analternating one with a positive half wave and a negative half waveinside a fiftieth second to two positive half waves in a fiftieth 50° ofsecond.

DZ1 is a zener diode operating to stabilize the voltage at a value of5.1V.

An electrolytic capacitor for filtering the voltage and transform itfrom an impulsive or pulse voltage to a DC voltage is moreover provided.

A resistor 23 operates to quickly discharge the energy stored by thecapacitor C1.

If a failure of the power supply occurs, this operation will allow themicroprocessor reset circuit to operate in a proper time and manner,while allowing a proper restarting and performing of the programinstructions, as the power supply voltage is reset.

The reference number 24 shows a filter ceramic capacitor, arranged nearthe microprocessor power supply pins.

The ceramic capacitor 24 operates to provide a higher immunity to theburst type of noises.

The reference number 25 shows a circuit branch designed for reading out,through the microprocessor analogic digital input, the signal sent bythe phototransistor FT1.

The level of this signal will be changed based on the light amountimpinging on the phototransistor, so as to increase or decrease itsconductivity toward the ground.

The fixed reference at +5 is obtained through the resistor R4.

The variable reference is just provided by the phototransistor.

The reference number 26 shows a circuit branch operating to read out,through the microprocessor analogic digital input, the signal sent bythe photoresistor FR1.

The level of this signal will be changed depending on the light amountimpinging on the photoresistor, to increase or decrease the resistivevalue thereof toward the ground.

The fixed reference at +5 is obtained through the resistor R6.

The variable reference is just given by the photoresistor.

The microprocessor, through an output pin thereof, will enable theswitching on or off of the red color LED diode DL1.

The current is limited by the series resistor R3.

The LED DL1 and the resistor R3 have been generally indicated by thereference number 27.

The component 28 is a flash type of microprocessor, the core of thesystem, with its on board software operating said electronic card.

In addition to the power supply, only three other pins will be used, toprovide as input and one as output.

The microprocessor operates at 4 Mhz and comprises an inner oscillatorand brown-out.

It has been found that the invention fully achieves the intended aim andobjects.

In fact, the invention provides a hairdryer including a safety deviceadapted to generate a signal signaling to the user that the filter isexcessively clogged, for allowing the hairdryer to properly and safelyoperate.

An advantage of the present invention is that the safety limits arespecifically preset by the maker, in designing the hairdryer, forproviding a timely cleaning operation.

Further advantages of the present invention are related to the fact thatthe device has a very reduced size and accordingly can be easily housedin a hairdryer, without occupying a lot of space which could hinder itsproper operation and that it is made by easily available materials andmethods.

In practicing the invention, the used materials, as well as thecontingent size and shapes, can be any, depending on requirements andthe status of the art.

1. A hairdryer including a safety device, characterized in that saidsafety device is adapted to detect a clogging, even partial, of a filterapplied to the hairdryer fan air inlet.
 2. A hairdryer, according toclaim 1, characterized in that said safety device comprises aphotosensor adapted to detect the light passing through the filter.
 3. Ahairdryer, according to claim 1, characterized in that, as the lightamount decreases because a clogging of the filter, jammed by dirty, saidsensor will send a signal which, through an electronic circuit, willoperate a signaling means.
 4. A hairdryer, according to claim 1,characterized in that said signaling means comprise a light indicatingelement which is switched on either with an intermittent or continuouslight.
 5. A hairdryer, according to claim 1, characterized in that saidhairdryer comprises a moisture sensor driven by said electronic circuit.6. A hairdryer, according to claim 1, characterized in that said filtercomprises a filter mesh screen made of a processed metal, plasticmaterial or TNT.
 7. A hairdryer, according to claim 1, characterized inthat said photosensor is arranged in a rear portion of the body of thehairdryer and under the suction filter.
 8. A hairdryer, according toclaim 1, characterized in that said hairdryer comprises a signalinglight indicating element arranged on the body of the hairdryer, andbeing visible from the outside of said body.
 9. A hairdryer, accordingto claim 1, characterized in that said hairdryer comprises an electroniccontrol circuit, which can be arranged at any region of the hairdryer.10. A hairdryer, according to claim 1, characterized in that, as aclogging, even partial, of the fan air inlet filter is detected, saidsafety device automatically causes said hairdryer to be switched off.11. A hairdryer, according to claim 1, characterized in that said safetydevice comprises an environment light detector allowing said safetydevice to properly operate even if the environment light is changed. 12.A hairdryer, according to claim 1, characterized in that said electroniccircuit comprises an electronic card including a single surface printedboard thereon are mounted the components necessary for operating saidelectronic circuit, a phototransistor, a photoresistor and a powersupply being arranged outside thereof.
 13. A hairdryer, according toclaim 1, characterized in that said phototransistor, as suitablyarranged, reads out the light amount passing through the mechanicalfilter of said hairdryer; said photoresistor, arranged at a differentposition than that of said phototransistor, reads out the environmentlight amount; the light amount being read by said phototransistordefining a condition of clean filter or dirty filter and, moreprecisely, beyond a value x, said filter being considered as dirty orclogged; the light amount read out by said photoresistor defining theenvironment light amount and, depending on this value, being performed afeedback to the value read out by the phototransistor, byproportionately translating the dirty filter values.
 14. A hairdryer,according to claim 1, characterized in that said card comprises thereona red color LED; said red color LED being held in a switched offcondition if said filter is clean; said red color LED being switched ononly if the card is power supplied and only as the filter is consideredas dirty; as the card is powered down, said LED being switched off andas it is switched on again, the light amounts on said photodetectorsbeing read-out again and being actuated said red LED depending on thisread-out.
 15. A hairdryer, according to claim 1, characterized in thatsaid card is powered up simultaneously with said fan motor, the amountof light both on said phototransistor and on said photoresistor beingcontrolled and the card operating as indicated up to its power down; thephotodetectors being read out after about a second from the card powerup, to allow the signals to be stabilized, and the following read-outsbeing performed repeatedly at even intervals up to the power down of thecard.
 16. A hairdryer, according to claim 1, characterized in that adirty filter signal is considered as valid only after some consecutiveseconds providing the same results; the same thing occurring for theclean filter signal, thereby preventing false read-outs due to noisesfrom occurring.
 17. A hairdryer, according to claim 1, characterized inthat, as a dirty filter condition is detected, said red LED is switchedon and being switched off if a new clean filter condition is detected,by the mode of operation as disclosed or as said card is switched off.18. A hairdryer, according to claim 1, characterized in that all thecomponents of the electronic circuit arranged downstream of the powersupply operate on a low voltage obtained by a starting middle voltageV.110÷250 ac a low voltage.
 19. A hairdryer, according to claim 1,characterized in that said electronic circuit comprises a resistor Rioperating for providing a potential difference at the ends thereof toprovide a low voltage due to a resistive drop, the high value of thiscomponent and its dissipated power operating to block the surge type ofnoises which can arrive at the power supply and cause the electroniccard to fail.
 20. A hairdryer, according to claim 1, characterized inthat said electronic circuit comprises a diode bridge designed formodifying the voltage wave shape from an alternating one with a positionhalf wave and a negative half wave inside a fiftieth of seconds to twopositive half waves inside a fiftieth second.
 21. A hairdryer, accordingto claim 1, characterized in that said electronic circuit comprises azener diode for stabilizing the voltage to a value of 5.1V.
 22. Ahairdryer, according to claim 1, characterized in that said electroniccircuit comprises an electrolytic capacitor operating to filter saidvoltage and transform it from a pulse voltage to a continuous or DCvoltage.
 23. A hairdryer, according to claim 1, characterized in thatsaid electronic circuit comprises a resistor for quickly discharging theenergy stored by said capacitor, as the power supply voltage fails; thisoperation being required by the microprocessor reset circuit to operatein a proper time and manner, while allowing a proper resetting andperforming of the program instructions, as the power supply voltage isreset.
 24. A hairdryer, according to claim 1, characterized in that saidelectronic circuit comprises a filter ceramics capacitor arranged nearthe power supply pins of the microprocessor, and operating to increasethe burst type of noise immunity.
 25. A hairdryer, according to claim 1,characterized in that said electronic circuit comprises an electroniccircuit branch operating to read-out, through a microprocessor analogicdigital input, the signal sent by said phototransistor; said signalchanging its level depending on the light amount impinging on saidphototransistor, thereby increasing or decreasing the conductivity ofsaid phototransistor toward the ground; the fixed reference to +5 beingobtained through the resistor R4; the variable reference being justprovided by said phototransistor.
 26. A hairdryer, according to claim 1,characterized in that said electronic circuit comprises an electroniccircuit branch operating to read-out, through a microprocessor analogicdigital input, the signal sent by said photoresistor; said signalchanging its level depending on the light amount impinging on saidphotoresistor thereby increasing or decreasing the resistive valuethereof toward the ground; the fixed reference at +5 being achievedthrough the resistor R6; the variable reference being just achieved bythe photoresistor.
 27. A hairdryer, according to claim 1, characterizedin that said microprocessor, through an output pin thereof, enables theswitching on or switching off of said red color LED diode DL1; thecurrent being limited by the series resistor R3.
 28. A hairdryer,according to claim 1, characterized in that said electronic circuitcomprises a flash type of microprocessor, the core of the system, withan on-board software for operating said electronic card; in addition tothe power supply being used only other three pins, two as inlet pins andone as outlet pin; said microprocessor operating at 4 Mhz and includingan inner oscillator and brown-out.